Angle dental handpiece



P. R. SKINNER ANGLE DENTAL HANDPIECE March 19, 1940.

Filed March 14, 1938 rIIV/ Er 77/1115? ",1 l

I Patented Mar. 19, 1940 g i tool, and any movement between these parts is parting from the spirit of the invention. 9 translated into an insecure holding of the tool, In the accompanying drawing: with resultant Wabbling or displacement of the Figure l is a centralvertical sectional View of of a tool which is rotated in use. In these con- Figure 2 is a sectional view of the head of the structions it is impossible to obtain a rigid lockhandpiece. ing of the tool in place even when the parts are Figure 3 is a transverse sectional view, taken accurately proportioned and unworn. This is on the line 3-3 of Figure 1'. 25 because that in the standard forms the latch is Figure 4 is a side View of a tool having the introducedinto a circumferential groove in the standard form of shank. shank of a tool to be rotated, to prevent With- Figure 5 is a longitudinal sectional view of the drawal of the tool, and there must be sufiicient member by which the shank of a tool is received :10 difference between the widths of the latch and and held during operation. I

groove to permit free'movements of the latch Figure 6 is a side view of the tool-receiving intoand out of the groove to make possible the member. necessary rapid'and easy introduction and lock- Figure 7 is a vertical sectional View of the ing and the withdrawal of a tool. Thus, in the locking ring by which a tool is secured in the use of the construction when new and in good tool-receiving member.

, v rotative part, in a manner to prevent any inthe body of the member. The bearing 4 is re- 45 1 drawals of tools to and from the holding. means, The main portion of the means for holding, 50

duced number of parts, whereby a rigid struc- 8 with which meshes the gear 6. The lower end 55 UNKTSE 11* STATES PATENT, OFFiCE 2,194,187 ANGLE DENTAL HANDPIECE 7 Perry R. Skinner, Amsterdam, N; Y.

Application March 14, 1938, Serial No. 195,916

3 Claims. (01. 219-9) This invention relates to angle dental handture occupying only the usual limited space, may pieces. In these instruments the principal reserve materially to lessen the common objectionquirement is that the shank of a burr or other able independentmovements of such parts, and toolgbc received by and retained in a holding consequent wear resulting in insecure holding of 5 member in a manner to prevent the slightest intools. 5

dependent movement of the shank after being i The invention resides in a construction having secured inplace and rotated for use. Obviously, the novel forms and arrangements of comanylooseness in the holding means of a boring p'onent parts, substantially as hereinafter deor other tool for dental work, where extreme scribed and claimed. s

10 accuracy of operation is necessary, results in the In the present illustration of the invention I 10 accomplishment of, unsatisfactory work. In the have shown an effective structure by which the holding and securing means commonly used there specified purposes are accomplished. It is to be are an unnecessary number of parts to which understood that changes in the forms and armovement is imparted in driving and securing a rangement oi the parts may be made without de- 1 latter. Commonly in the usual constructions the the head of an angle dental handpiece, having greatest wear takes place because of the fact the improved tool-receiving and retaining means 20 that a latch or its equivalent, secured to a nonarranged therein, a tool being shown in position 20. rotating part. is brought to engage the shank to be attached for use.

. condition there is objectionable independent In thisdrawing the hollow head of the hand-" movement of the tool, and the permitted movepiece into which the shank of a tool is introment, increases as wear takes place in the latch duced and secured is shown as composed of two and in the walls of the groove in the shank of the separable sections I and 2, to permit ready in- 40 toolQf 1 troduction and removal of the operative parts,

One purpose which I have in view is to pro- The lower part i of the head has formed in it a vide in instruments of the kind referred to means bearing 3 for the end of a tool-receiving member,

whereby the shank of a tool may be secured in and arranged mainly in the upper portion is a position for use and readily be attached to a tubular removable bearingfi of a size to receive dependent movement of the tool. Another purcessed at one side, at 5, to receive a bevel gear pose is to provide an attaching means of the 8 through which motion is imparted to a toolkind specified, which shall be so formed that any receiving member. Secured to the gear 6 is a wear caused by repeated introductions and withshaft 7 to be rotated in the usual manner.

and operations of tool-attaching means, shall aurotating and securing a tool in place in the head .tomatically be compensated for. Also, I have in of the instrument, is composed of a member 8. view to provide tool-holding, driving and securing This member is cylindrical in general form and means in dental instruments, composed of a rehas formed with it a circumferential bevel gear of the member 8 is shaped to conform to the bearing 3 in the interior of the head, and the upper face of the gear 5! is plane, forming a surface III which bears upon the lower end of the bearing 4.

In assembling the parts, the upper portion of the tool-receiving member 8 is introduced into the bearing 4 to bring the bearing to bear upon the surface IQ of the member. The member 8 is then placed in position in the section I of the head of the instrument, the gear 6 is placed in position to engage the bevel gear 6 of the member 8, the section 2 of the head is placed to receive the upper end of the member, and finally the sections are secured in place. When the parts are arranged as described the inner end of the gear 6 bears against the wall of the recess in the bearing, and, therefore, rotation of the latter is prevented in the operation of the tool. The construction described permits easy and rapid substitution of a new bearing for a worn one and thus permits of the use of the other parts of the instrument on which little wear is imposed for an indefinite time.

For the purpose of making use of the fewest possible number of parts necessary for receiving, rotating and securing a tool in operative position, the member 8, first, has a central longitudinal opening IE which corresponds in diameter to that of the standard tool, and thus forms a tool-receiving member. The member has extending into its interior 2. lug or projection I2 of a form to be received by the recess I3 in side of the shank Id of a tool at the end of the shank, to cause the tool to rotate with the member, and it has a slot I5 in its wall to receive a projection of a locking member, such projection being introduced into and retained in the circumferential groove I6 located near the end of the shank of the tool to secure the tool during use.

The means employed in the present form of the invention for securing a tool from withdrawal from the member 8 consists of a ring or collar I? having an inwardly extending lug I8. This ring or collar is of a size to be received by the upper reduced end 19 0f the member 8, and when in place rests upon a seat 20 at the base of the reduced end. Extending from the outer end of the portion I9 to a point intersecting the slot I5, is a slot 2| of a size to permit the passage through it of the projection I8 of the ring or collar when the latter is being placed in position to bear upon its seat 20.

The slot 2I in the member 8 intersects the slot I5 in such member at a position in line with the lug or projection I2, and from the point of intersection the slot I5 extends around approximately two-thirds of the diameter of the member and at an angle upwardly.

The ring or collar It has formed on its outer face a series of serrations or teeth 22, and arranged on the casing of the tool is a spring-held brake or stop 23 which is adapted to be brought to engage the teeth or projections to prevent the rotation of the ring or collar with the reduced portion of the member 8 with which the ring or collar is normally rotated. The brake or stop 23 is herein shown as formed with a resilient arm 24 attached to the casing of the instrument which normally maintains the brake out of contact with the teeth of the ring or collar. The casing of the head is provided with a slot 25 through which the arm 24 extends, the slot being of a size corresponding to that of the arm, so that possibility of the entrance of moisture or fine particles to the interior of the head is prevented.

In the use of the tool-receiving and locking means the shank of a tool is introduced into the member 8 and brought to a position to cause the lug or projection l2 to enter the recess I3 in the shank, thus insuring the rotation of the parts in unison. When the shank is positioned as described, its circumferential groove I6 is in line with the end of the slot I5 which intersects the lower end of the slot 2i. The initial position of the ring or collar is that in which its projection I8 extends through the member 8 at the point where the two slots intersect and, therefore, in line with the groove I6 of the shank and into the recess IS in the shank. When the parts are in the positions described, the brake is brought to engage the locking ring or collar, and the member 8 is given a partial rotation in the direction indicated by the arrows, which is the direction in which the tool is rotated during use. As the member 8 and the tool are rotated, the projection I8 is caused to enter the slot I5 in the member 8 and also to enter the groove I6 in the shank of the tool, thus preventing the withdrawal of the latter. Because of the inclination of the slot I5 it will be apparent that as the shank of the tool is prevented from longitudinal movement by contact with the lug I2, the passage of the projection I8 in the slot I5 will cause a pressure on the upper wall of the groove I6 and thus exert a force to lock the shank in place in a manner to prevent even the slightest movement. The rotation of the tool in the direction indicated, at all times during use, tends to force the locking projection upwardly in the inclined slo l5, insuring the firm holding of a tool during use.

The removal of a tool may quickly be accomplished by applying the brake or stop to the locking ring or collar and by giving a sufficient rotation to the member 8 to free the locking projection from the slot i5 and from the groove I6 in the shank of the tool, and cause it to abut against the wall of the slot 2!. of the parts the locking projection extends into the recess I3 in the shank, leaving the tool free to be withdrawn.

The described construction provides an improved receiving, driving, locking, and releasing means for a dental tool, composed of only two parts. As these parts by their forms prevent, during the holding and operation of a tool, any independent movements, wear on them is reduced to a minimum. Besides, any wear, however slight, is automatically compensated for by reason of the cooperation of the locking projection and the inclined surface upon which the projection bears and upon which it is maintained thus insuring the requisite rigid holding of a tool during use.

I claim:

1. An instrument of the kind described comprising a rotatable tool-receiving member having an elongated inclined opening in its side, and a locking, member carried by the tool-receiving member, capable of limited rotation thereon, and having a projection adapted to extend through the inclined opening and to enter a groove in a tool to retain the latter, the parts being so disposed that in the rotation of the tool-receiving member the projection is forced against the wall of the groove in the tool to secure the tool in locked position.

2. An instrument of the kind described com- In this position LII prising a tubular rotatable tool-receiving member having a longitudinal slot extending from its end and a circumferential opening extending obliquely from the slot, and a locking member consisting of a ring or collar encircling the tool-receiving member and having a projection adapted to be introduced through the slot and to be moved into or out of the oblique opening, the projection being of a length to enter a groove in a tool carried in the tool-receiving member, to retain the tool, or to be removed from the groove to release the tool.

3. An instrument of the kind described comprising a tubular rotatable tool-receiving member having a longitudinal slot extending from its end and a circumferential opening extending obliquely from the slot, a locking member consisting of a ring or collar encircling the toolreceiving member, and having a projection adapted to be introduced through the slot and to be moved into or out of the oblique opening, the projection being of a length to enter a groove in a tool carried in the tool-receiving member, to retain the tool, or to be removed from the groove to release the tool, and a brake or stop movable to engage the ring or collar andcheck its rotating with the tool-receiving member.

PERRY R. SKINNER. 

